The Five Biggest Disasters in American Military History

Nations often linger on their military defeats as long as, or longer than, they do on their successes. The Battle of Kosovo remains the key event of the Serbian story, and devastating military defeats adorn the national narratives of France, Russia and the American South. What are the biggest disasters in American military history, and what effect have they had on the United States?

In this article, I concentrate on specific operational and strategic decisions, leaving aside broader, grand-strategic judgments that may have led the United States into ill-considered conflicts. The United States may well have erred politically in engaging in the War of 1812, World War I, the Vietnam War and Operation Iraqi Freedom, but here I consider how specific failures worsened America’s military and strategic position.

Invasion of Canada

At the opening of the War of 1812, U.S. forces invaded Upper and Lower Canada. Americans expected a relatively easy going; the notion that Canada represented the soft underbelly of the British empire had been popular among American statesmen for some time. Civilian and military leaders alike expected a quick capitulation, forced in part by the support of the local population. But Americans overestimated their support among Canadians, overestimated their military capabilities, and underestimated British power. Instead of an easy victory, the British handed the Americans a devastating defeat.

American forces (largely consisting of recently mobilized militias) prepared to invade Canada on three axes of advance, but did not attack simultaneously and could not support one another. American forces were inexperienced at fighting against a professional army and lacked good logistics. This limited their ability to concentrate forces against British weak points. The Americans also lacked a good backup plan for the reverses that the British soon handed them. None of the American commanders (led by William Hull, veteran of the Revolutionary War) displayed any enthusiasm for the fight, or any willingness to take the risks necessary to press advantages.

The real disaster of the campaign became apparent at Detroit in August, when a combined British and Native American army forced Hull to surrender, despite superior numbers. The British followed up their victory by seizing and burning several American frontier outposts, although they lacked the numbers and logistical tail to probe very deeply into American territory. The other two prongs of the invasion failed to march much beyond their jumping off points. American forces won several notable successes later in the war, restoring their position along the border, but never effectively threatened British Canada.

The failure of the invasion turned what Americans had imagined as an easy, lucrative offensive war into a defensive struggle. It dealt a major setback to the vision, cherished by Americans, of a North America completely under the domination of the United States. Britain would hold its position on the continent, eventually ensuring the independence of Canada from Washington.

Battle of Antietam

In September 1862, Robert E. Lee invaded Maryland with the Army of Northern Virginia. Lee’s objectives were to take advantage of foraging opportunities (the movement of armies across Virginia had left the terrain devastated), support a revolt in Maryland and potentially inflict a serious defeat on Union forces. Unfortunately for Lee, information about his battle disposition fell into the hands of General George McClellan, who moved to intercept with the much larger Army of the Potomac. President Lincoln saw this as an opportunity to either destroy or badly maul Lee’s army.

The Battle of Antietam resulted in 22,000 casualties, making it the bloodiest day in the history of the Americas. Despite massive numbers, a good working knowledge of Lee’s dispositions and a positional advantage, McClellan failed to inflict a serious defeat on the Confederates. Lee was able to withdraw in good order, suffering higher proportional casualties, but maintaining the integrity of his force and its ability to retreat safely into Confederate territory.

McClellan probably could not have destroyed the Army of Northern Virginia at Antietam (19th-century armies were devilishly difficult to annihilate, given the technology available), but he could have dealt it a far more serious setback. He vastly overestimated the size of Lee’s force, moved slowly to take advantage of clear opportunities and maintained poor communications with his subcommanders. A greater success at Antietam might have spared the Army of the Potomac the devastation of Fredericksburg, where Union forces launched a pointless direct assault against prepared Confederate positions.

Antietam was not a complete failure; the Army of Northern Virginia was hurt, and McClellan forced Lee out of Maryland. President Lincoln felt confident enough following the battle to issue the Emancipation Proclamation, promising to free slaves in rebellious states. Nevertheless, Antietam represented the best opportunity that the Union would have to catch and destroy the Army of Northern Virginia, which remained one of the Confederacy’s centers of gravity until 1865.